Apple's "Handoff" -- one of the key new features of iOS 8 and OS X Yosemite -- will work only on newer Macs that support Bluetooth 4.0 and the Bluetooth LE (low energy) technology, according to an Apple engineering manager.

While Apple didn't mention Handoff requirements when it unveiled the feature at its Worldwide Developers Conference (WWDC) earlier this month, a developer-only session there made it clear that Bluetooth LE is necessary.